I've got mine 65% C, 15% S, 10% I, 5% F and 5% G. I dont think ive ever met any two people with the same setups, so I can't really say whats a good idea. I figured I have almost 40yrs before I can touch my tsp money anyways so being more aggresive now won't hurt all that much in the long run. when choosing, I looked at the charts that go with the description of each one, and decided to put more money in funds that historically did the better when the investment worth was compared to inflation, but everyone has their own reasons for setting theirs up they way they do. I think its a good idea to put as much money in TSP as you feel you can spare. After all any type of savings is better then no savings (that and im the type of person who knows they will be tempted to spend their money when it isn't tied up.)